A consumption meter may be used for measuring utility usage in connection with supply of the utility, e.g. of water, gas, heating, or cooling, and may in turn be used in connection with charging of the consumed quantity. Consumption meters may be used in connection with district heating, district cooling and/or distributed water or gas supply.
By way of measuring principle, consumption meters may be based on ultrasonic flow measurement and include an ultrasonic flow meter part. Thus an ultrasonic flow meter may be a transit time flow meter arranged to measure a flow rate of a fluid flowing in a flow channel by use of known operation principles for transit time flow meters.
Other parameters than the flow rate may be of interest to the operator of a utility supply line as well. Thus with consumption meters relating to utilities like water, heating and cooling it is customary that the meter comprises one or more temperature sensors to measure the temperature of the supplied fluid, either for billing purposes as with heating and cooling applications, or for survey purposes relating to e.g. bacterial growth or freezing warnings as with water supply applications. Also sensors relating to measurement of the pressure are known with flow meter technology of the prior art.
One elegant type of pressure sensor is a strain gauge. According to the prior art strain gauges may be applied with flow meters to determine the flow rate, e.g. according to the Venturi principle.
Thus GB 801,334 to General Electric discloses a fluid flow meter with a curved tube which has strain gauges attached to the tube at a fixed end of the tube, where the tube walls are thinner than elsewhere. The curved tube changes the direction the flow, and the reactive forces are measured by the strain gauges so as to calculate the flow rate based on the strain gauge readings.
Likewise with U.S. Pat. No. 7,237,440 B2 to CIDRA Corporation a combination of strain sensors and ultrasonic sensors is applied to measure a pressure field, e.g. in terms of vertical disturbances, moving with a process flow, and to measure the speed of sound propagating through the fluid flowing in a pipe.
Strain gauges may as well be applied with flow meter technology to control the flow meter.
U.S. Pat. No. 5,731,527 to Micro Motion, Inc. discloses a Coriolis flow meter wherein flow tubes employing anisotropic materials such as fiber reinforced composites are equipped with strain gauges to detect the internal pressure of the tube and the stress created by the wall deformation.
Likewise, EP 1 426 741 A1 to Krohne AG discloses a Coriolis mass through-flow meter with strain gauges for pressure measurements. With the through-flow meter a strain gauge is attached to the flow tube and further coupled to a pressure signal unit to read out a pressure signal based on the signal from the strain gauges, which in turn may be used to correct the mass flow rate signal outputted by the Coriolis mass through-flow meter for the pressure of the medium flowing therein.
Whereas the above applications of strain gauges are directed towards operation of flow meters per se, i.e. for local operation or control thereof, there is still as need for a system of consumption meters which is capable of measuring consumption data as well as data relating to the utility network pressure and to communicate these data to an operator of the utility network.